I havn't been around in a while due to mother nature going to town on Australia and all that. But at last I'm back into rhythm and its time to build something.
I know its not really what you see around here, but I'v decided to make a coil gun
I'm sure a lot of you already know what it is, but for those who don't, a coil gun works of electromagnetic fields. The general gist, is that using some for of transformer (often disposable camera flash charging circuits) a capacitor bank is charged to a high voltage (300V+). Once charged, all this stored energy is dumped into a coil designed specifically for the type of projectile being used. This creates a big electromagnetic force for a couple of milliseconds, enough to accelerate the projectile into the coil, and by the time it reaches the center of the coil, the magnetic field should cease to exist. The projectile then continues out of the barrel.
Now, for all those who are about to tell me that I can't achieve a massive fps which can go through 7 feet of solid concrete and cause a minor earthquake in the southern hemisphere, I know this.
I do however hope to achieve somewhere around 150-200 fps, using small caliber projectiles. Likely 3mm ball bearings. HOPEFULLY these small projectiles won't prove to be a b***h due to the whole "bigger ferromagnetic things are more effected than smaller ones" idea.
Ok, so onto how I plan to achieve this.
Charging Circuit:
Well first up I suppose I will go the generic way and use disposable camera circuits. Not just one though, multiple crammed together to greatly reduce the charging time, hopefully to around a few seconds.
Only problem with these is that they are very inefficient, something like 16% efficiency which might not cut it. So later in the year when I get access to printing circuit boards at uni I might make a DC-DCHV boost transformer. Much more efficient and faster.
Capacitor Bank:
Found myself a nice large 1000uF 450V capacitor on fleabay. This saves me using multiple smaller caps. I will probably charge these to about 400v depending on the capabilities of the charger circuit.
Loading:
I plan on this gun being semi auto, which means it will have two coils. One main coil for projectile acceleration, and a second much less powerful coil as an injector coil. The beauty of this project is that nothing needs to be air tight! Sweet relief.
Basically the injector coil is what will be activated when you pull the trigger, it will pull a rod through it which will push the round forward to the main coil. As the round reaches the main coil, the pushing rod will then close a contact switch which will fire the main coil. The pushing rod will be spring loaded so it will be pulled back to its originally position. This should all happen very very fast. Iv attempted to explain this process in a pic below.
Triggering:
This will be handled by a relay switch due to the large currents and voltages that travel through the circuit.
The rest:
The whole gun will be housed in a sexy plexiglass handgun enclosure, with all your usual flashing led's and such that come with an electrical project like this.
Voltage of the capacitors will be read on a digital display.
Thats about all I can think of. One hell of a rant, but its been a while
